#include<stdio.h>
#define u8 unsigned char
#define u32 unsigned long

// S盒
const u8 Sbox[256] = {
	0xd6,0x90,0xe9,0xfe,0xcc,0xe1,0x3d,0xb7,0x16,0xb6,0x14,0xc2,0x28,0xfb,0x2c,0x05,
	0x2b,0x67,0x9a,0x76,0x2a,0xbe,0x04,0xc3,0xaa,0x44,0x13,0x26,0x49,0x86,0x06,0x99,
	0x9c,0x42,0x50,0xf4,0x91,0xef,0x98,0x7a,0x33,0x54,0x0b,0x43,0xed,0xcf,0xac,0x62,
	0xe4,0xb3,0x1c,0xa9,0xc9,0x08,0xe8,0x95,0x80,0xdf,0x94,0xfa,0x75,0x8f,0x3f,0xa6,
	0x47,0x07,0xa7,0xfc,0xf3,0x73,0x17,0xba,0x83,0x59,0x3c,0x19,0xe6,0x85,0x4f,0xa8,
	0x68,0x6b,0x81,0xb2,0x71,0x64,0xda,0x8b,0xf8,0xeb,0x0f,0x4b,0x70,0x56,0x9d,0x35,
	0x1e,0x24,0x0e,0x5e,0x63,0x58,0xd1,0xa2,0x25,0x22,0x7c,0x3b,0x01,0x21,0x78,0x87,
	0xd4,0x00,0x46,0x57,0x9f,0xd3,0x27,0x52,0x4c,0x36,0x02,0xe7,0xa0,0xc4,0xc8,0x9e,
	0xea,0xbf,0x8a,0xd2,0x40,0xc7,0x38,0xb5,0xa3,0xf7,0xf2,0xce,0xf9,0x61,0x15,0xa1,
	0xe0,0xae,0x5d,0xa4,0x9b,0x34,0x1a,0x55,0xad,0x93,0x32,0x30,0xf5,0x8c,0xb1,0xe3,
	0x1d,0xf6,0xe2,0x2e,0x82,0x66,0xca,0x60,0xc0,0x29,0x23,0xab,0x0d,0x53,0x4e,0x6f,
	0xd5,0xdb,0x37,0x45,0xde,0xfd,0x8e,0x2f,0x03,0xff,0x6a,0x72,0x6d,0x6c,0x5b,0x51,
	0x8d,0x1b,0xaf,0x92,0xbb,0xdd,0xbc,0x7f,0x11,0xd9,0x5c,0x41,0x1f,0x10,0x5a,0xd8,
	0x0a,0xc1,0x31,0x88,0xa5,0xcd,0x7b,0xbd,0x2d,0x74,0xd0,0x12,0xb8,0xe5,0xb4,0xb0,
	0x89,0x69,0x97,0x4a,0x0c,0x96,0x77,0x7e,0x65,0xb9,0xf1,0x09,0xc5,0x6e,0xc6,0x84,
	0x18,0xf0,0x7d,0xec,0x3a,0xdc,0x4d,0x20,0x79,0xee,0x5f,0x3e,0xd7,0xcb,0x39,0x48
};
	
// 密钥扩展算法的常数FK 
const u32 FK[4] = {
	0xa3b1bac6, 0x56aa3350, 0x677d9197, 0xb27022dc
};

// 密钥扩展算法的固定参数CK 
const u32 CK[32] = {
	0x00070e15, 0x1c232a31, 0x383f464d, 0x545b6269,
	0x70777e85, 0x8c939aa1, 0xa8afb6bd, 0xc4cbd2d9,
	0xe0e7eef5, 0xfc030a11, 0x181f262d, 0x343b4249,
	0x50575e65, 0x6c737a81, 0x888f969d, 0xa4abb2b9,
	0xc0c7ced5, 0xdce3eaf1, 0xf8ff060d, 0x141b2229,
	0x30373e45, 0x4c535a61, 0x686f767d, 0x848b9299,
	0xa0a7aeb5, 0xbcc3cad1, 0xd8dfe6ed, 0xf4fb0209,
	0x10171e25, 0x2c333a41, 0x484f565d, 0x646b7279
};

u32 functionB(u32 b); // 查S盒的函数B 
u32 loopLeft(u32 a, short length); // 循环左移函数 
u32 functionL1(u32 a); // 线性变换L
u32 functionL2(u32 a); // 线性变换L'
u32 functionT(u32 a, short mode); // 合成变换T
void extendFirst(u32 MK[], u32 K[]); // 密钥扩展算法第一步
void extendSecond(u32 RK[], u32 K[]); // 密钥扩展算法第二步
void getRK(u32 MK[], u32 K[], u32 RK[]); // 轮密钥获取算法
void iterate32(u32 X[], u32 RK[]); // 迭代算法
void reverse(u32 X[], u32 Y[]); // 反转函数 
void encryptSM4(u32 X[], u32 RK[], u32 Y[]); // 加密算法
void decryptSM4(u32 X[], u32 RK[], u32 Y[]); // 解密算法
 
/*
	查S盒的函数B 
	参数:	u32 b
	返回值:	查S盒的结果u32 b
*/ 
u32 functionB(u32 b) {
	u8 a[4];
	short i;
	a[0] = b / 0x1000000;
	a[1] = b / 0x10000;
	a[2] = b / 0x100;
	a[3] = b;
	b = Sbox[a[0]] * 0x1000000 + Sbox[a[1]] * 0x10000 + Sbox[a[2]] * 0x100 + Sbox[a[3]];
	return b;
}

/*
	循环左移算法
	参数：	u32 a    length：循环左移位数
	返回值：u32 b 
*/
u32 loopLeft(u32 a, short length) {
	short i;
	for(i = 0; i < length; i++) {
		a = a * 2 + a / 0x80000000;
	}
	return a;
}

/* 
	密钥线性变换函数L
	参数：	u32 a
	返回值：线性变换后的u32 a	
*/
u32 functionL1(u32 a) {
	return a ^ loopLeft(a, 2) ^ loopLeft(a, 10) ^ loopLeft(a, 18) ^ loopLeft(a, 24);
}

/* 
	密钥线性变换函数L'
	参数：	u32 a
	返回值：移位操作后的u32 a	
*/
u32 functionL2(u32 a) {
	return a ^ loopLeft(a, 13) ^ loopLeft(a, 23);
}

/*
	合成变换T
	参数：	u32 a    short mode：1表示明文的T，调用L；2表示密钥的T，调用L' 
	返回值：合成变换后的u32 a 
*/
u32 functionT(u32 a, short mode) {
	return mode == 1 ? functionL1(functionB(a)) : functionL2(functionB(a));
}
 
/* 
	密钥扩展算法第一步
	参数：	MK[4]：密钥  K[4]:中间数据，保存结果	（FK[4]：常数） 
	返回值：无 
*/ 
void extendFirst(u32 MK[], u32 K[]) {
	int i;
	for(i = 0; i < 4; i++) {
		K[i] = MK[i] ^ FK[i]; 
	} 
}

/* 
	密钥扩展算法第二步
	参数：	RK[32]：轮密钥，保存结果    K[4]：中间数据 （CK[32]：固定参数） 
	返回值：无
*/ 
void extendSecond(u32 RK[], u32 K[]) {
	short i;
	for(i = 0; i <32; i++) {
		K[(i+4)%4] = K[i%4] ^ functionT(K[(i+1)%4] ^ K[(i+2)%4] ^ K[(i+3)%4] ^ CK[i], 2);
		RK[i] = K[(i+4)%4];
	} 
}

/*
	密钥扩展算法 
	参数：	MK[4]：密钥     K[4]：中间数据    RK[32]：轮密钥，保存结果 
	返回值：无 
*/ 
void getRK(u32 MK[], u32 K[], u32 RK[]) {
	extendFirst(MK, K);
	extendSecond(RK, K);
}

/*
	迭代32次
	参数：	u32 X[4]：迭代对象，保存结果    u32 RK[32]：轮密钥
	返回值：无	  
*/
void iterate32(u32 X[], u32 RK[]) {
	short i;
	for(i = 0; i < 32; i++) {
		X[(i+4)%4] = X[i%4] ^ functionT(X[(i+1)%4] ^ X[(i+2)%4] ^ X[(i+3)%4] ^ RK[i], 1);
	}
}

/*
	反转函数 
	参数；	u32 X[4]：反转对象    u32 Y[4]：反转结果
	返回值：无 
*/
void reverse(u32 X[], u32 Y[]) {
	 short i;
	 for(i = 0; i < 4; i++){
	 	Y[i] = X[4 - 1 - i];
	 } 
} 

/*
	加密算法
	参数：	u32 X[4]：明文    u32 RK[32]：轮密钥    u32 Y[4]：密文，保存结果 
	返回值：无 
*/
void encryptSM4(u32 X[], u32 RK[], u32 Y[]) {
	iterate32(X, RK);
	reverse(X, Y);
} 

/*
	解密算法
	参数： 	u32 X[4]：密文    u32 RK[32]：轮密钥    u32 Y[4]：明文，保存结果
	返回值：无 
*/
void decryptSM4(u32 X[], u32 RK[], u32 Y[]) {
	short i;
	u32 reverseRK[32];
	for(i = 0; i < 32; i++) {
		reverseRK[i] = RK[32-1-i];
	}
	iterate32(X, reverseRK);
	reverse(X, Y);
}
 
/*
	测试数据：
	明文：	01234567 89abcdef fedcba98 76543210
	密钥：	01234567 89abcdef fedcba98 76543210
	密文：	681edf34 d206965e 86b3e94f 536e4246 
*/
int main(void) {
	u32 X[4]; // 明文 
	u32 MK[4]; // 密钥 
	u32 RK[32]; // 轮密钥  
	u32 K[4]; // 中间数据 
	u32 Y[4]; // 密文 
	short i; // 临时变量 
	printf("明文："); 
	scanf("%8x%8x%8x%8x", &X[0], &X[1], &X[2], &X[3]);
	printf("密钥："); 
	scanf("%8x%8x%8x%8x", &MK[0], &MK[1], &MK[2], &MK[3]);
	printf("**************生成轮密钥*****************\n"); 
	getRK(MK, K, RK);
	for(i = 0; i < 32; i++) {
		printf("[%2d]：%08x    ", i, RK[i]);
		if(i%4 == 3)	printf("\n"); 
	}
	printf("************** 生成密文 *****************\n"); 
	encryptSM4(X, RK, Y);
	printf("%08x %08x %08x %08x\n", Y[0], Y[1], Y[2], Y[3]);
	printf("************** 生成明文 *****************\n");  
	decryptSM4(Y, RK, X);
	printf("%08x %08x %08x %08x\n", X[0], X[1], X[2], X[3]);
	return 0;	
} 
